FLI question: Attempted to dereference a pointer to aggregate type... [structs/unions in structs/unions]

Hi everybody,

I'm trying to translate something like this from C to Lisp:

  typedef struct {
    int one;
    int two;
    struct {
      int three;
      int four;
    } bar;
  } foo;

I first tried this:

  (define-c-struct foo
    (one :int)
    (two :int)
    (bar (:struct (three :int)
                  (four :int))))

Then this:

  (define-c-struct bar
    (three :int)
    (four :int))

  (define-c-struct foo
    (one :int)
    (two :int)
    (bar bar))

And then this:

  (define-c-typedef bar-struct (:struct bar))

  (define-c-struct foo
    (one :int)
    (two :int)
    (bar bar-struct))

All three definitions are accepted by LispWorks, but in none of
these cases am I able to access the slots THREE and FOUR - I
always get:

  "Attempted to dereference a pointer to aggregate type..."

What is the right idiom to do this?

And, actually, the real problem is even more complicated as I
have to deal with a struct which contains a union of two other
structs.  But I think the short example above demonstrates where
I can't proceed.

Thanks in advance for your help,
Edi.

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